Cloth has been fashioned into a variety of garments (e.g., clothes and gowns used in hospitals), medical drapes and dressings, diapers, and other useful mammalian body coverings. Cloth is defined in its broadest sense to be fabric or material formed by weaving, knitting, knotting, pressing, bonding, crocheting, interlocking, interlacing, melt-blowing, or felting of natural or synthetic yarns, filaments, or fibers. Nonlimiting examples of cloth include woven, knitted or non-woven fabrics and webs, used as body coverings.
The traditional methods of fastening one portion of the cloth to another portion of the cloth have included strings, buttons, zippers, pins, snap fasteners, and hook and loop fasteners. Such fastening means conventionally used may be bulky, unwieldy, or incompatible with the necessity of adhering cloth to the skin of individuals wearing the body covering or to other portions of the cloth for easy and rapid securement. For example, in surgical arenas, one or more cloth drapes may be employed to cover portion(s) of a patient undergoing surgery. Some drapes must be adhered to a patient's skin. Other drapes are often fastened to the drapes adhered to the skin. Conventional forms of mechanical fastening are inappropriate or inconvenient.
Pressure sensitive adhesive tapes have been used with garments, drapes and dressings, and diapers which are meant to be disposed after a single use as solid waste. Examples of pressure sensitive adhesive tapes which have been employed for such disposable items include water insoluble styrene-isoprene-styrene block copolymers with tackifying resins, vinyl ethers, and high molecular weight acrylate copolymers having minimal amounts of plasticizing monomer therein.
Cloth for body coverings may be disposed or retained after use. If retained, soiled cloth must be cleaned after use, usually by laundering in soapy water, an aqueous alkali solution. For medical and surgical use, the cloth must also be sterilized by autoclavation after laundering and before use. The expense of some cloth such as linen demands that the fastening means also be reusable or replaceable at a reasonable cost.
Various mechanical fastening means subjected to repeated sterilizations in an autoclave may not survive repeated cleanings. The mechanical fastening means may be too expensive to be replaced for each repeated use of the cloth. Pressure sensitive adhesive tapes presently useful for disposable garments, drapes, dressings and diapers are not formulated to endure repeated use under such sterilizing and cleaning conditions. And such pressure sensitive adhesive tapes do not disperse during cleaning.
Water-dispersible pressure sensitive adhesives have been made for paper making and printing operations which require splicing of the end of one roll of paper to the beginning of another roll.
Examples of such water-dispersible pressure sensitive adhesives include U.S. Pat. Nos. 3,865,770; 4,413,080; and 4,569,960 (Blake), U.S. Pat. No. 3,441,430 (Peterson), and U.S. Pat. No. 2,838,421 (Sohl). Blake discloses water-dispersible pressure sensitive adhesives for splicing carbonless paper which comprise a blend of acrylate:acrylic acid copolymers and systems which include tackifiers, plasticizers, and neutralizers. Peterson discloses aggressively water soluble tacky adhesives composed of a copolymer of a mono-carboxylic acid and an alkoxy-alkyl ester, a plasticizer having at least one ether linkage, a cross linker, and up to two parts of a copolymer of the hydroxide of a monovalent cation. The hydroxide is used to neutralize sulfuric acid generated during the decomposition of a potassium persulfate catalyst used for copolymerization. Sohl discloses a mixture of water-soluble polyvinyl carboxylic acid and a compatible hydroxy-polyalkylene permanent elasticizer which retains adequate tackiness and internal, cohesive strength even when exposed for a week or more at humidities in the range from 0 to 90% relative humidity.
Two other water soluble pressure sensitive adhesive compositions are disclosed in U.S. Pat. No. 4,413,082 (Gleichenhagen et al.) Gleichenhagen et al. 4,341,680 (Hauber et al.). Gleichenhagen et al. discloses a composition comprising a copolymer of acrylic acid butyl ester and vinyl carboxylic acid, and a plasticizer. The copolymer, which contains free carboxyl groups is neutralized almost completely by the addition of potassium hydroxide, preferably in excess. Gleichenhagen et al. discloses the neutralization with potassium hydroxide normally brings about an excellent solubility of the pressure sensitive adhesive composition in water, even at widely varying pH values, but also exerts a strongly positive influence on the adhesive properties (especially tack and cohesion) which can be further enhanced by over-neutralization (use of an excess of KOH). Hauber et al. discloses a mixture of a copolymer of a monomeric ethyl acrylate and a monomeric .alpha.,.beta. unsaturated aliphatic monocarboxylic acid and a tertiary, ethoxylated n-alkyl alkane diamine, where from 50% to 90% of the acid groups of the monocarboxylic acid are neutralized.
Another water soluble pressure sensitive pressure adhesive composition for papermaking tapes is disclosed in European Patent Publication 0 352 442 (Zbignliew Czech). The composition is a water-soluble contact adhesive based on a polyvinyl carbonic acid with at least one softener containing a hydroxyl group with a molecular weight below 1000 and curing agents used to process paper.
Another water-soluble pressure sensitive adhesive composition for photographic papermaking repulpable tapes is disclosed in U.S. Pat. No. 3,152,940 (Abel et al.) The preferred composition is an alkali-soluble copolymer of acrylic acid ester and acrylic acid and a water-soluble wax of hydroxy polyalkylene material which remains cohesive and tacky when exposed either to dry or humid atmospheric conditions.
Another repulpable acrylic acid based pressure sensitive adhesive is disclosed in U.S. Pat. No. 4,338,432 (Eskay). The composition for making water-dispersible tapes for papermaking is a copolymer of an acrylic acid compound, which is a homopolymer of acrylic acid or a copolymer of acrylic acid and esters of acrylic acid or methacrylic acid, a polyhydric alcohol plasticizer-tackifier, and a minor amount of monobasic caustic. Amounts of the base higher than 2.5 percent cause the adhesive to become elastic in nature rather than tacky.
Another water-soluble pressure sensitive adhesive for papermaking tapes is disclosed in U.S. Pat. No. 3,096,202 (deGroot von Arx). Polyvinylpyrrolidone, a polyfunctional monomeric cross-linking agent, a compatible plasticizer, and an activator catalyst to induce vinyl-type polymerization are combined to produce a water-soluble, normally tacky pressure sensitive adhesive retaining its adhesiveness after subjection to elevated temperatures.
European Patent Publication 0 297 451 (Knutson et al.) discloses a hot melt adhesive activated by moisture which is water soluble and alkali dispersible to be recycled with paper products. The hot melt adhesive comprises an N-acyl-polyalkyleneimine and an acid functional compound.
Another water soluble adhesive useful with paper products such as decals, labels, and bumper stickers is disclosed in U.S. Pat. No. 3,763,117 (McKenna et al.). The composition which has aggressive tack and aqueous alkali removability comprises a hydroxy bearing monomer, a softening acrylate or methacrylate comonomer, and optionally, a hardening comonomer of either vinyl esters of alkanoic acids, ethyl or methyl acrylates, ethyl or methyl diesters of maleic or fumaric acids, acrylonitrile, methacrylonitrile, styrene, or vinyl chloride.
A transfer or splicing tape is disclosed in U.S. Pat. No. 3,890,292 (Bohme et al.). The tape is formed with a water dispersible adhesive composition of ionomeric copolymers of hydrophilic and hydrophobic monomers. The ionic monomer comprises a water soluble alkali metal salt of an .alpha.,.beta. unsaturated monocarboxylic acid. The water soluble nonionic monomers are polyalkylene oxide condensation products. The composition maintains excellent tack characteristics at both high and low humidities and have improved moisture stability properties.
Each of these prior water-dispersible or water-soluble pressure sensitive adhesives has been used in paper making or with paper products not used as mammalian body coverings, although passages in the Blake patents and the Peterson patent also identify use with cloth labels coated with water-dispersible or water-soluble adhesive, respectively, which may be readily washed from garments to which they are affixed.
The sensitivity of mammalian skin to chemicals which contact the skin requires specific compositions to minimize allergic or toxic reaction between the adhesive components and the sensitive skin of the individual. Commercially available tackifiers useful for industrial operations such as papermaking can generate allergic or toxic reactions when compositions comprising such industrially acceptable tackifiers are placed in contact with mammalian skin.
Prior use of disposable mammalian body coverings, e.g., garments, drapes and dressings, and diapers has been found to increase environmental concerns and solid waste disposal issues. Reusable cloth body coverings, e.g., garments such as hospital gowns, drapes and dressings, and diapers have economic and environmental advantages. But the use of cloth items must be tempered by the ability to find a suitable fastening system.